Several Basic Properties of Textile Fibers

1. Moisture Absorption Properties of Fibers

When textile fibers are placed in the air, they constantly exchange moisture with the air; that is, the fibers continuously absorb moisture from the air while simultaneously releasing moisture into the air.

The ability of textile fibers to absorb or release moisture is called their hygroscopicity. Hygroscopicity is one of the important physical properties of textile fibers.

The degree of hygroscopicity of textile fibers has a certain influence on their shape, size, weight, and physical and mechanical properties, thus affecting their processing and usage performance.

The degree of moisture absorption of textile fibers also directly affects the wearing comfort of clothing fabrics. Fibers with high moisture absorption capacity easily absorb sweat excreted by the human body, regulate body temperature, relieve the feeling of dampness and stuffiness, and thus make people feel comfortable. Therefore, the moisture absorption properties of fibers should be considered in commercial trade, fiber performance testing, textile processing, and the selection of textiles.

Among common textile fibers, wool, linen, viscose, silk, and cotton have strong moisture absorption capabilities, while synthetic fibers generally have poor moisture absorption. Vinylon and nylon have slightly better absorption, acrylic is worse, polyester is even worse, and polypropylene and chlorofiber have almost no moisture absorption.

Currently, synthetic fibers with poor moisture absorption are often blended with natural fibers or viscose fibers with strong moisture absorption to improve the moisture absorption capacity of textiles.

In addition to hygroscopicity, the water absorption of fiber materials is also closely related to the wearing comfort of clothing fabrics. Fiber water absorption refers to the fiber's ability to absorb liquid water.

2. Mechanical Properties of Fibers

The various deformation properties of textile fibers under the action of various external forces are called the mechanical properties of textile fibers. External forces include various forms such as tension, compression, bending, torsion, and friction.

The mechanical properties of textile fibers should include fiber strength, elongation, elasticity, abrasion resistance, and modulus of elasticity.

Fiber Strength: Fiber strength refers to its ability to resist external damage, largely determining the durability of textile products.

Fiber Abrasion Resistance: Fibers and their products experience wear and tear during processing and use due to constant friction. Fiber abrasion resistance refers to its ability to withstand external abrasion. It is closely related to the durability of textile products. The quality of abrasion resistance is an important indicator of the performance of clothing fabrics. Fiber abrasion resistance is related to factors such as the fiber's macromolecular structure, supramolecular structure, breaking elongation, and elasticity.

The order of abrasion resistance of common fibers from highest to lowest is as follows: Nylon > Polypropylene > Vinylon > Polyethylene > Polyester > Acrylic > Chlorinated Fiber > Wool > Silk > Cotton > Linen > High-tenacity fiber > Cuprammonium fiber > Viscose fiber > Acetate fiber > Glass fiber.

3. Fiber Chemical Resistance

The chemical resistance of fibers refers to their resistance to damage from various chemical substances.

During textile dyeing and finishing processes, fibers come into contact with water, acids, alkalis, salts, and other chemicals to varying degrees. Simultaneously, fiber products come into contact with various chemicals, such as detergents and finishing agents, during use. Therefore, textile fibers must possess certain chemical resistance properties to meet the requirements of textile dyeing and finishing processes and product use. Furthermore, only by understanding the chemical resistance properties of various textile fibers can appropriate processing conditions be selected and various fiber products used correctly. Among various textile fibers, cellulose fibers have strong resistance to alkalis but weak resistance to acids; protein fibers have different chemical resistance properties compared to cellulose fibers, being more resistant to acids than to alkalis. Protein fibers will be damaged to varying degrees, even decomposed, in both strong and weak alkalis; synthetic fibers have stronger chemical resistance than natural fibers, such as polypropylene and chlorofiber, which have excellent acid and alkali resistance.

4. Linear Density and Length of Fibers and Yarns

The linear density of a fiber refers to its fineness, while the length of a fiber refers to its length. Textile fibers must possess a certain linear density and length to allow them to bind together and be spun into yarn through inter-fiber friction. Therefore, a certain linear density and length are essential conditions for textile processing and for creating usable products.

The linear density of textile fibers is closely related to the properties of the yarns and fabrics produced. Generally, lower fiber linear density and better uniformity are beneficial for textile processing and product quality. Regarding the impact of fiber linear density on fabric performance, fabrics made from finer fibers are softer and have a gentler luster. Finer fibers can also be used to make lighter and thinner fabrics. They can also be used to create breathable fabrics with a silk-like effect, but fabrics made from fine fibers are prone to pilling and fuzzing; while coarser fibers can be used to create stiffer, more robust, and thicker fabrics. Similarly, the length of textile fibers is also closely related to the quality of textiles and products. Longer fiber length, better length uniformity, and a lower content of short fibers are beneficial for textile processing and product quality. Under the same conditions, longer fibers result in higher yarn strength, more uniform sliver, and a smoother yarn surface. The resulting fabrics have better durability, a smoother appearance, and are less prone to pilling and fuzzing. Furthermore, provided the yarn quality is maintained, longer fibers produce finer yarns, which can be used to manufacture lighter and thinner fabrics. For shorter fibers, length is more important than linear density; for example, length is the most important indicator in cotton grading and pricing.

In textile fibers, the linear density and length of natural fibers are not uniform, sometimes significantly so, depending on the fiber variety and growth conditions. In contrast, chemical fibers are artificially manufactured, and their linear density and length can be controlled and determined within a certain range according to the requirements of fiber processing and use. Bulk yarn is made by first blending two fibers with different shrinkage rates into yarn, and then treating the yarn with steam, hot air, or boiling water. During this process, the fiber with the higher shrinkage rate shrinks more and is located in the center of the yarn, while the low-shrinkage fiber, due to its smaller shrinkage, is compressed onto the surface of the yarn, forming loops. This results in a fluffy, full, and elastic bulky yarn.

Linear density is one of the most important physical and geometric characteristics of fibers. It not only affects textile processing and product quality but is also closely related to the performance of fabrics. Similarly, linear density is also the most important indicator of yarn, affecting the physical and mechanical properties, feel, and style of textiles. It is also one of the important bases for fabric design.

The linear density of fibers and yarns can be expressed in various ways, but it is generally expressed using indirect indicators proportional to the cross-sectional area of ​​the yarn. Commonly used indicators include tex (count), metric count, English count, and denier.

5. Characteristics of Commonly Used Fibers

(1) Natural Fibers:

COTTON: Absorbent and soft.

Linen: Wrinkles easily, but becomes crisp and breathable after finishing; relatively expensive.

Ramie: A type of linen with coarser yarn; typically used for curtains or sofa fabrics. When used in clothing, it's usually blended with linen.

Wool: Fine yarn, less prone to pilling.

Larmswoo: Coarser yarn, generally blended with ANCYLIC (acrylic polyacrylonitrile fiber) to prevent garment deformation.

Mohair: Fluffy and warm.

Cashmere: Fine fibers, lightweight and soft, comfortable to the touch.

Angora: Fine, loose yarn, smooth to the touch, elastic; relatively expensive.

Silk: Soft, with a beautiful luster, highly absorbent.

(2) Chemical Fibers:

Rayon: Very lightweight and soft; often used in collection shirts. Polyester: Similar to rayon, it's easy to handle, wrinkle-resistant after ironing, and inexpensive.

Spadex: Naturally elastic, it's often blended with cotton. Even a 5%-10% content provides significant elasticity, making garments less prone to deformation and fading. It's more expensive.

Nylon: Completely non-breathable, with a stiffer feel. Suitable for trench coats and outerwear. Blended with wool, it gives garments a more structured look.